Paramagnetic

Definition

Paramagnetic materials are substances that have unpaired electrons and are attracted to external magnetic fields. This behavior is due to the presence of these unpaired electrons, which generate a magnetic moment that aligns with the applied field, leading to magnetization. Unlike ferromagnetic materials, paramagnetic materials do not retain their magnetization once the external magnetic field is removed.

5 Must Know Facts For Your Next Test

1. Paramagnetic materials are characterized by having one or more unpaired electrons, which lead to their magnetic properties.
2. The degree of paramagnetism is quantified by a property called magnetic susceptibility, which is positive for paramagnetic materials.
3. Common examples of paramagnetic materials include aluminum, platinum, and certain metal ions like iron(III).
4. When placed in a magnetic field, paramagnetic materials align their magnetic moments parallel to the field, leading to a net attraction.
5. Paramagnetism is generally much weaker than ferromagnetism, and the effect disappears once the external magnetic field is removed.

Review Questions

• How do unpaired electrons contribute to the behavior of paramagnetic materials in an external magnetic field?
  • Unpaired electrons in paramagnetic materials create individual magnetic moments that can align with an external magnetic field. When exposed to this field, the moments of these unpaired electrons tend to orient parallel to the applied field, resulting in a net attraction toward the magnetic source. This alignment is temporary and ceases once the external field is removed, showcasing how crucial unpaired electrons are in defining paramagnetism.
• Compare and contrast paramagnetic and diamagnetic materials regarding their magnetic properties and responses to an external magnetic field.
  • Paramagnetic materials have unpaired electrons that lead to a net positive susceptibility and attraction to external magnetic fields, while diamagnetic materials possess only paired electrons and exhibit negative susceptibility, resulting in a weak repulsion from magnetic fields. In a magnetic field, paramagnetic substances will be attracted and align their moments with the field direction, whereas diamagnetic substances will show no significant alignment or response beyond their slight repulsion.
• Evaluate the implications of paramagnetism on material selection in technological applications such as MRI technology.
  • Paramagnetism has significant implications for technology like MRI because materials with paramagnetic properties can enhance image contrast. The presence of unpaired electrons in certain contrast agents leads to an increased response in an external magnetic field used during imaging. Understanding these properties allows for better design choices in selecting agents that improve diagnostic capabilities, highlighting how the fundamental principles of magnetization directly influence practical applications.

Related terms

Ferromagnetism:

A phenomenon where certain materials can become permanently magnetized due to the alignment of their magnetic moments in the same direction.

Diamagnetic: Materials that have all their electrons paired and are slightly repelled by magnetic fields, showing no permanent magnetization.

Magnetic Susceptibility: A measure of how much a material will become magnetized in an applied magnetic field, indicating the strength of its magnetic response.